The ZEST-3 signal amplifier is a useful tool for connecting the tachograph to the ABS, speed limiter, retarder, motor brake, etc. It is used when the tachograph signal output can not provide enough current for multiple devices at a time. The outputs are independent of each other, so that any fault - overload, disconnection, breakdown on the positive pole of the battery, etc. - is transmitted without interruption to the remaining intact channels. The amplifier is connectable to the 12V and 24V installations. In state metrology centers for tachographs, car manufacturers, ZEST-3 can be used to test more electronic tachographs and speedometers.